The end-systolic pressure-volume relationship and ventriculoarterial coupling in patients undergoing coronary artery...

The end-systolic pressure-volume relationship and analysis of ventriculoarterial coupling have been established as a useful tool to determine the left ventricular performance and arterial loading conditions. The purpose of this study was to evaluate the end-systolic pressure-volume relationship and ventriculoarterial coupling in anesthetized patients with either a normal heart or coronary artery disease (CAD) using a transesophageal echocardiography (TEE) monitor.

Sixteen patients with CAD and 4 patients without ischemic disease were studied. The end-systolic volume of the left ventricle was obtained by TEE, and the end-systolic pressure was obtained from the brachial arterial dicrotic pressure. In order to obtain the end-systolic pressure-volume relationship, we plotted 7 different left ventricular end-systolic pressures against the corresponding left ventricular end-systolic volumes during the pressure manipulation. The linear regression obtained by this method was designated as the end-systolic elastance (Ees). Furthermore, we calculated the effective arterial elastance (Ea) using the pressure-volume framework.

We divided the patients with CAD into 3 groups: Group A: left ventricular ejection fraction (LVEF) > 50%, Group B: LVEF 35-50%, Group C: LVEF < 35%. We also studied a control group (Group D) who did not suffer from an ischemic heart condition. Ees in group C (1.4 +/- 0.2) was lower than in the other 3 groups (P < 0.05). Ea/Ees in group C (1.9 +/- 0.1) was greater than in group A (0.7 +/- 0.1), group B (1.0 +/- 0.06) and group D (0.6 +/- 0.1)(P < 0.05). There were no significant differences in Ees and Ea/Ees between group A and group D.

We found that patients with CAD and a normal LVEF had a physiological Ea/Ees identical to the control subjects. We also demonstrated that patients with CAD and a reduced LVEF showed a deterioration in Ea/Ees.